The Gunners drew 1-1 with the La Liga giants at the Emirates last week, a disappointing result considering Atletico played the majority of the fixture with ten men after Sime Vrsaljko was sent off for two rash tackles.

The Europa League is Arsene Wenger's last chance to win some silverware - and go out on a high - before he stands down after 22 years in charge at the end of the season.

Here are five things we noticed as Arsenal trained in the rain ahead of their trip to sunny Spain for the most important fixture of their season to date.

1. Henrikh Mkhitaryan is in contention

The Armenian was forced off the pitch in Arsenal's 2-1 defeat by Manchester United last time out, after netting an equaliser for the Gunners.

Mkhitaryan has been suffering with a knee injury he picked up in the quarter-final of the Europa League against CSKA Moscow, and is yet to recover fully.

The Armenian was forced off the pitch against Manchester United (Image: PA)

Mkhitaryan was in training with the rest of his team-mates on Wednesday (Image: Action Images via Reuters)

There were major fears that a recurrence of the injury would rule him out of the return leg of the semi-final in Spain this Thursday.

But the former Red Devils midfielder was in training with the rest of his team-mates on Wednesday, and looks fit to feature for the Gunners.

2. Big performance needed

Arsenal's strikers have seemingly been starved of confidence for so long, but it is the defence who has been letting the team down recently.

Alexandre Lacazette looks much more like the £56million striker Arsenal thought they were getting in recent weeks, while the ineligible Pierre-Emerick Aubameyang can't stop scoring in the Premier League.

Danny Welbeck was a handful up front in the first leg at the Emirates last week (Image: Action Images via Reuters)